<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../js/jquery-1.10.1.min.js"></script>
  <style>
    * {
      padding: 0;
      margin: 0;
    }

    .wrap {
      width: 400px;
      height: 400px;
      background-color: red;
      margin: 100px;
      overflow: hidden;
      /* position:relative; */
    }

    .sub {
      width: 300px;
      height: 300px;
      background-color: orange;
      margin: 50px;
      overflow: hidden;
      position: relative;
    }

    .txt {
      width: 100px;
      height: 100px;
      background-color: #000;
      margin: 100px;
    }
  </style>
</head>

<body>
  <div class="wrap">
    <div class="sub">
      <div class="txt"></div>
    </div>
  </div>
</body>
<script>
  // $(ele).offset()  => 返回匹配的元素相对于 文档左上角的偏移   {left,top}
  console.log($(".txt").offset());  // {left,top}
  console.log($(".txt").offset().left, $(".txt").offset().top);

</script>

</html>